This invention relates to the field of electromagnetic signal transmission. More particularly, this invention relates to an electromagnetic window and method of construction thereof for broad bandwidth signal transmission for microwave communication and radar.
Current electromagnetic window constructions principally involve monolithic ceramic or plastic materials of constant and uniform dielectric properties. The effective bandwidth of these materials decreases as both dielectric constant of the material increases and as the frequency of signal transmission increases. A need exists for electromagnetic windows capable of broad band frequency transmission. Even more particularly, a need exists for electromagnetic windows capable of broad band frequency transmission having good thermal characteristics and rain erosion characteristics for use in high speed missiles and aircraft. Presently known electromagnetic window systems do not meet these requirements.
It is well known that multilayer radome wall construction offers enhanced bandwidth capability. However, the problem of realizing the combination of required dielectric constant values with required thicknesses for the layers has been difficult with the currently used materials. Furthermore, at the higher frequencies for mm-wave systems where the wavelength of a layer is small the layers must be very thin. The methods for construction and fabrication now in use cannot meet the tolerances needed.